Fixes column header drop indicator (#18925)

Calculation of the frozen column width was wrong in multiselect mode.
It did not take into account the last frozen column, but added
the select column twice.
The same problem was in AutoScroller (as the same methods were
copy-pasted there), for which reason the autoscrolling was not
scrolling till the end.
This patch fixes the calculation error and removes copy-pasted code,
reusing the same code in both places.

Change-Id: I164e2fc96688088b620ad8785c533c593723f83e

2 files changed, 19 insertions, 33 deletions

diff --git a/client/src/com/vaadin/client/widget/grid/AutoScroller.java b/client/src/com/vaadin/client/widget/grid/AutoScroller.java
index 90d206d98b..9cc238ac15 100644
--- a/client/src/com/vaadin/client/widget/grid/AutoScroller.java
+++ b/client/src/com/vaadin/client/widget/grid/AutoScroller.java
@@ -610,22 +610,25 @@ public class AutoScroller {
         }
     }
 
-    private double getFrozenColumnsWidth() {
-        double value = getMultiSelectColumnWidth();
-        for (int i = 0; i < grid.getFrozenColumnCount(); i++) {
+    public double getFrozenColumnsWidth() {
+        double value = 0;
+
+        for (int i = 0; i < getRealFrozenColumnCount(); i++) {
             value += grid.getColumn(i).getWidthActual();
         }
+
         return value;
     }
 
-    private double getMultiSelectColumnWidth() {
-        if (grid.getFrozenColumnCount() >= 0
-                && grid.getSelectionModel().getSelectionColumnRenderer() != null) {
-            // frozen checkbox column is present
-            return getTheadElement().getFirstChildElement()
-                    .getFirstChildElement().getOffsetWidth();
+    private int getRealFrozenColumnCount() {
+        if (grid.getFrozenColumnCount() < 0) {
+            return 0;
+        } else if (grid.getSelectionModel().getSelectionColumnRenderer() != null) {
+            // includes the selection column
+            return grid.getFrozenColumnCount() + 1;
+        } else {
+            return grid.getFrozenColumnCount();
         }
-        return 0.0;
     }
 
     private double getMaxScrollLeft() {
diff --git a/client/src/com/vaadin/client/widgets/Grid.java b/client/src/com/vaadin/client/widgets/Grid.java
index ccc909465f..a77499e41f 100644
--- a/client/src/com/vaadin/client/widgets/Grid.java
+++ b/client/src/com/vaadin/client/widgets/Grid.java
@@ -4113,7 +4113,8 @@ public class Grid<T> extends ResizeComposite implements
 
             dropMarkerLeft += autoScrollX;
 
-            final double frozenColumnsWidth = getFrozenColumnsWidth();
+            final double frozenColumnsWidth = autoScroller
+                    .getFrozenColumnsWidth();
             final double rightBoundaryForDrag = getSidebarBoundaryComparedTo(dropMarkerLeft);
             final int visibleColumns = getVisibleColumns().size();
 
@@ -4156,7 +4157,8 @@ public class Grid<T> extends ResizeComposite implements
                     .min(sidebarBoundary, gridBoundary);
 
             // Do not show on left of the frozen columns (even if scrolled)
-            final int frozenColumnsWidth = (int) getFrozenColumnsWidth();
+            final int frozenColumnsWidth = (int) autoScroller
+                    .getFrozenColumnsWidth();
 
             left = Math.max(frozenColumnsWidth, Math.min(left, rightBoundary));
 
@@ -4317,25 +4319,6 @@ public class Grid<T> extends ResizeComposite implements
             autoScroller.stop();
         }
 
-        private double getFrozenColumnsWidth() {
-            double value = getMultiSelectColumnWidth();
-            for (int i = 0; i < getFrozenColumnCount(); i++) {
-                value += getColumn(i).getWidthActual();
-            }
-            return value;
-        }
-
-        private double getMultiSelectColumnWidth() {
-            if (getSelectionModel().getSelectionColumnRenderer() != null) {
-                // frozen checkbox column is present, it is always the first
-                // column
-                return escalator.getHeader().getElement()
-                        .getFirstChildElement().getFirstChildElement()
-                        .getOffsetWidth();
-            }
-            return 0.0;
-        }
-
         /**
          * Returns the amount of frozen columns. The selection column is always
          * considered frozen, since it can't be moved.
@@ -4436,7 +4419,7 @@ public class Grid<T> extends ResizeComposite implements
                 return;
             }
 
-            double position = getFrozenColumnsWidth();
+            double position = autoScroller.getFrozenColumnsWidth();
             // iterate column indices and add possible drop positions
             for (int i = frozenColumns; i < getColumnCount(); i++) {
                 Column<?, T> column = getColumn(i);
@@ -8714,4 +8697,4 @@ public class Grid<T> extends ResizeComposite implements
         }
         return null;
     }
-}
+}
\ No newline at end of file